EEC681781 Distributed Computing Systems Discussion1 Chapter 12 Wenbing

EEC-681/781 Distributed Computing Systems Discussion#1 (Chapter 1&2) Wenbing Zhao wenbing@ieee. org

2 • Q 1: What is the role of middleware in a distributed system? Fall Semester 2008 EEC-681: Distributed Computing Systems Wenbing Zhao

3 • Q 2: Explain what is meant by (distribution) transparency, and give examples of different types of transparency. Fall Semester 2008 EEC-681: Distributed Computing Systems Wenbing Zhao

4 • Q 3: Why is it sometimes so hard to hide the occurrence and recovery from failures in a distributed system? Fall Semester 2008 EEC-681: Distributed Computing Systems Wenbing Zhao

5 • Q 4: Why is it not always a good idea to aim at implementing the highest degree of transparency possible? Fall Semester 2008 EEC-681: Distributed Computing Systems Wenbing Zhao

6 • Q 5: What is an open distributed system and what benefits does openness provide? Fall Semester 2008 EEC-681: Distributed Computing Systems Wenbing Zhao

7 • Q 6: Describe precisely what is meant by a scalable system. Fall Semester 2008 EEC-681: Distributed Computing Systems Wenbing Zhao

8 • Q 7: Scalability can be achieved by applying different techniques. What are these techniques? Fall Semester 2008 EEC-681: Distributed Computing Systems Wenbing Zhao

9 • Q 8: What is the difference between a vertical distribution and a horizontal distribution? Fall Semester 2008 EEC-681: Distributed Computing Systems Wenbing Zhao

10 • Q 9: Why are transport-level communication services often inappropriate for building distributed applications? Fall Semester 2008 EEC-681: Distributed Computing Systems Wenbing Zhao

11 • Q 10: Suppose you could make use of only transient synchronous communication primitives. How would you implement primitives for transient asynchronous communication? Fall Semester 2008 EEC-681: Distributed Computing Systems Wenbing Zhao

12 • Q 11: Explain why transient synchronous communication has inherent scalability problems, and how these could be solved. Fall Semester 2008 EEC-681: Distributed Computing Systems Wenbing Zhao

13 • Q 12. The most prominent benefit of the publish/subscribe model is the increased scalability if the number of consumers per message (created by a producer) is large. Understand this benefit by comparing the number of transport-level messages needed to propagate an application-level message to, say, 3 consumers, using the two different messaging models (queue-based and publish/subscribe). Fall Semester 2008 EEC-681: Distributed Computing Systems Wenbing Zhao